Crappy idle when cold

Geevaaa9112

Registered User
When I start my car when cold, it will idle like its choking, the vac will go down to around 5-10. When i try to rev it up to even it out, sometimes the revs will stick and come down really slow. It will stop doing this after the temperature reaches normal level. I just did my spark plugs and wires, and it was fine for about 2 weeks. Before that I have replaced all of the sensors in the car. Any one have any suggestions?
 
One uneducated guess is the motor is running lean, from base computer settings for a cold start, from recall it is way lean for EPA regs.
What I did was change the cold start air fuel ratio on my SCT chip.

The EEC varies AF ratio according to temperature at coldstart, and I was having a similar problem getting it to idle smoothly at startup, when the temp was below 60 F.
So I copied the AFR for 32 F into the 60 F spot in the program and it works.
In my case, since I changed a coulple of things, the 'adaptive learning' of the EEC computer would never get it right from 60 F to 32F.
 
Geevaaa9112 said:
When I start my car when cold, it will idle like its choking, the vac will go down to around 5-10. When i try to rev it up to even it out, sometimes the revs will stick and come down really slow. It will stop doing this after the temperature reaches normal level. I just did my spark plugs and wires, and it was fine for about 2 weeks. Before that I have replaced all of the sensors in the car. Any one have any suggestions?

DIS maybe?
another thread with the opposite effect reminds me of this....
good luck!
paul
 
When I tried driving it today, it still did the crappy idle at cold of course. And when i had it at normal temp, i tried to let it idle by itself, within a couple of minutes the motor died out. I was just adding this info to get some more suggestions. Im gonna take a look at the connections to all the sensors. Anymore suggestions are greatly appreciated. Thanks guys
 
I talked to my mechanic, and he said it could be the coolant temp sensor not working properly. It is making the car run lean when cold. Where is this sensor located? Is it the sensor with one wire coming of it, underneath the air inlet tube, that goes into a metal coolant line?
 
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